Device for determining the oxygen potential of a atmosphaere at high temperatures

摘要

1,177,630. Determining oxygen potential, electrically. G. K. N. GROUP SERVICES Ltd. April 10, 1967 [April 12, 1966], No.15870/66. Heading G1N. A probe for determining the "oxygen potential" of atmospheres in furnaces, ovens and flues at temperatures of the order of 650‹ C. to 1100‹ C., comprises a tube 10 of a fired refractory material which is an impervious solid anionic electrolyte, an outer electrode 23 of platinum-rhodium alloy wire wound under tension round the tube near its closed end 11, and an inner electrode 18 of a body of randomly wound platinum-rhodium alloy wire pressed into close contact with the end of the tube by a leaf-spring 21 acting through a rigid rod 15. In use, the outer electrode is in contact with the atmosphere under test and the inner electrode is in contact with a reference gas, e.g. air or pure oxygen. The tube 10 may be of zirconia, containing calcium oxide or magnesium oxide. The electrodes and the leads 17, 22 preferably contain at least 13% rhodium to resist the high temperatures and prevent embrittlement or stretching of the outer electrode under reducing conditions. The output voltage of the probe may be measured using a very high impedance instrument such as a valve voltmeter or a chart recorder with an impedance matching arrangement. A capacitor may be connected across the terminals of the apparatus to eliminate the effects of electrical interference. It is stated that it is possible to measure oxygen partial pressures down to 10SP-20/SP atmospheres.